Z-Scores

Question 1

What is a z-score?

Answer 1

Standardized variable, the amount of standard deviations away from the mean

Question 2

What is the z-score equation?

Answer 2

z = (x - μ) / σ

x = x-value
μ = mean
σ = standard deviation

Question 3

What’s the difference between positive and negative z-scores?

Answer 3

A positive standard score is above the mean, while a negative standard score is below the mean.

Question 4

Practice problem:
Sarah got a test score of 77%
- The standard deviation of the test was 7%
- Sarah’s z-score was .57

What is the mean of the class??

Answer 4

73%

Question 5

What units do z-scores have?

Answer 5

none!